Fuel control and ignition apparatus



Sept. 8, 1959 s. L. KILE FUEL CONTROL AND IGNITION APPARATUS Filed Sept. 11, 1953 INVENTOR. Stephen L. [Ci/1e BY 0120 3911 9 United States Patent Office 2 ,903,053 Patented Sept. 8, 1959 2,903,053 FUEL CONTROL AND IGNITION APPARATUS Stephen L. Kile, Whitefish Bay, Wis, assignor to Baso Inc., Milwaukee, Wis., a corporation of Wisconsin Application September 11, I953, Serial No. 379,619 7 Claims. (Cl. =158--128) This invention relates to control apparatus including improved means for interlocking a device powered by alternating current and a device powered by thermoelectric current. More particularly, the invention relates to improved fuel control and ignition apparatus for providing safe lighting in fluid fuel burning equipment.

In fluid fuel burning apparatus provided with electric ignition, means must be provided for positively shutting "off all fuel flow to the main burner while the igniter is functioning to ignite the fuel issuing from the pilot burner. Unless this is done, raw gas can issue from the main burner to cause an explosive flash-out of the gas. This is obviously a hazardous condition.

In the prior art, attempts at providing the aforementioned main fuel shut-01f have included the use of a solenoid valve in the main fuel line, together with switch means for opening the power circuit to the solenoid valve upon closure of the circuit to the igniter. This arrangement does not afford absolute safety, since gravity is normally relied upon to close solenoid valves. Moreover, solenoid valves are known to stick in the open position as a result 'of gumming or of residual magnetism.

Generally, apparatus burning fluid fuel utilizes a safety shut-elf valve powered by a thermoelectric generator subject to the heat of a pilot burner flame. Safety shutoff valves of the type now in general use are not susceptible of sticking in the "open position, since they are provided with spring means biasing the valve toward closed position, and they do not rely on gravity for closing forces. It is therefore a general object of the present invention to provide an improved fuel control and ignition apparatus in which a spring-biased thermoelectric-ally powered valve is utilized not only for its normal function including shutting of main fuel flow upon pilot outage, but is also utilized for shutting off main fuel flow during ignition of the pilot burner.

Another object of the invention is to provide an improved apparatus including a unit powered by alternating current and also including a thermoelectrically powered device, said apparatus having an improved electrical interlock for actuating the thermoelectric device whenever alternating current is supplied to said alternating current unit.

More specifically, it is an object of the invention to provide in fluid fuel burning apparatus having a main burner and including electric ignition means as well as t'h'errnoelectrically powered spring-biased valve means, an improved electrical interlock which positively insures actuation of the valve means to safety position whenever the circuit to the electric ignition means is completed, thereby rendering it impossible to energize the ignition means while fuel is flowing to the main burner.

Another object of the invention is to provide an improved apparatus of the aforementioned character wherein the interlock includes electrical coupling means or connections, either direct or inductive, between the alternating current circuit and the thermoelectric circuit, whereby alternating current is superimposed upon the 2 thermoelectric current in the thermoelectric circuit whenever alternating current flows in said alternating current circuit, superimposition of said alternating current causing the current in the thermoelectric circuit to decrease to a value such as to effect the actuation of said thermoelectric device.

A more specific object of the invention is to provide an improved apparatus of the character described where'- in a transformer connected to an alternating current source is connected in circuit with both an igniter and a thermoelectrically powered main burner valve, whereby alternating current flows from said transformer to said igniter and to said valve simultaneously, thereby causing closure of said valve and preventing all main burner fuel flow whenever said igniter is energized.

Another object of the invention is to provide an improved apparatus of the character described which is simple and inexpensive in construction, positive "and efficient in operation, and otherwise well adapted for the purposes described.

Further objects and advantages of the invention will appear as the description proceeds, reference being had to the accompanying drawing illustrating two forms of the invention.

In the drawing:

Figure l is a semi-diagrammatic view illustrating one form of improved fuel control and ignition apparatus having a manually resettable safety shut-off valve incorporated therein; and s Figure 2 is a view similar to Figure 1 and illustrating another form of the invention utilizing a single transformer instead 'of two transformers.

Referring more particularly to Figure 1 of the drawing, the invention is shown semi-diagrammatically as applied to a fuel control and ignition apparatus includ ing a safety shut-off valve and an igniter. However, the invention is not limited to the illustrated applications but may also be applied to any other equipment wherein it is desired to provide an interlock between a unit powered by alternating current and a thermoelectrically powered device.

Referring now to Figure l, the numeral 5 indicates a thermoelectrically powered device which in the embodiment illustrated in said figure takes the form of a thermoelectrically powered manually resettable safety shut-off valve which may be of the general type disclosed in the Charles V. Hildebrecht Patent No. 2,114,446, issued April 19, 1938. The numeral 6 indicates an alternating current powered unit which in the illustrated embodiment takes the form of an electrical resistance coil which functions as a fuel igniter and is mounted in coacting proximity to a pilot burner 7. The pilot burner 7 is, in turn, mounted adjacent a main burner 8, and a thermoelectric generator 9, which may take the form of a thermocouple, is mounted in a position to have its hot junction subject to the heat of the flame of the pilot burner. An electroresponsive valve 50, which may take the form of a solenoid valve, is interposed in the fuel supply pipe 15 and controls the flow of fuel to the main burner 8. A condition responsive circuit controlling device, which may take the form of a thermostat 51, controls the flow of current to the solenoid valve 50 from a source 52, and through the valve 50 controls the flow of fuel to the burner in accordance with fluctuations in temperature.

The safety shut-off valve 5 controls the flow of fuel to both the pilot burner 7 and the main burner 8, said valve having a body 10 provided with a fuelinlet 11, a pilot fuel outlet 13, and a main burner fuel outlet 12. A fuel supply pipe 14 connects the inlet 11 with a suitable source of gaseous fuel, and fuel supply pipes 15 and 16 connect outlets 12 and 13 with the main burner and pilot burner respectively.

The details of construction of the valve will not be set forth herein, reference being had to the referred to the Patent No. 2,114,446 for this purpose. Suffice it for the purposes of this application to state that said valve has a movable valve member 17 which is biased toward a seat 18 by a spring 19, and, when seated, provides 100 percent shut-off of the main burner and pilot burner fuel. The valve member 17 is connected to an armature 20 by means of a stem 21, said armature being positioned to coact with an electromagnet 22 having a coil 23. When the armature 20 abuts the pole faces of the magnet 22, the valve member 17 is in the open position shown. When the attractive force of the electromagnet 22 on the armature 20 decreases to a value below the force exerted by the spring 19, said spring simultaneously pulls the armature 20 from the magnet pole faces and snaps the valve 17 onto the seat 18.

In the illustrated embodiment of the invention the safety shut-off means includes a reset mechanism 24 having a reciprocatory reset stem 45 which carries a manually engageable reset button 25 at its outer end and is operable to reset the armature 20 to the electromagnet pole faces upon actuation of the button 25. Additionally, the safety shut-off valve 5 includes flow interruption means which may take the form of a flow interruption disk 46 which provides interruption of the flow of fuel to the main burner during actuation of the button 25, while at the same time permitting fuel flow to the pilot burner in the manner set forth in detail in Patent No 2,114,446, and for a purpose to be hereinafter de scribed.

While the thermoelectrically powered devices selected for illustration take the form of manually resettable safety shut-off valves, it is to be understood that the invention contemplates the use of other suitable thermoelectrically powered devices, for example a thermoelectrically powered switch. In the case of thermoelectrically powered switches, the latter may be utilized to control the operation of electromagnetically operated valves which may be located adjacent or remote therefrom.

The thermoelectric circuit of the illustrated embodiment of the invention includes the thermoelectric generator 9 which is connected in series circuit relationship with the electromagnetic coil 23 through the conductors 26, 27 and 28, and through the secondary winding 29 of a step-down transformer 30. During normal operation of the fuel burning equipment of which the improved apparatus forms a part, the thermoelectric current generated by the generator 9 energizes the electromagnet 22 sufficiently to hold the armature 20 to the pole faces of the electromagnet, and the valve member 17 is thereby held in the open position shown. This thermoelectric current is a direct current of predetermined steady value depending upon the construction of the thermoelectric circuit. Under normal conditions, when this thermoelectric current decreases in value by a predetermined amount to what may be termed the drop-out value, for example on cooling of the thermocouple after pilot outage, the electromagnet releases the armature 21 to effect closure of the valve member 17 under the bias of the spring 19.

The igniter 6 receives its energization from an alternating current source, and depending upon the voltage of said source, a step-downtransformer 34 may be inter posed between the igniter and said source. The igniter 6 is connected in series circuit relationship with the sec ondary winding 33 of the transformer 34 through a ballast resistor 32, the primary Winding of the transformer and conductors 35, 36, 37 and 38. The primary winding 39 of the transformer 34 is connected to the alternating current source, which may be that which exists in the usual house lighting mains by means of conductors 40 and 41, there being a normally open switch 42 interposed 4 in the latter conductor for controlling the flow of alternating current in the apparatus.

The ballast resistor 32 is utilized in the igniter circuit in order to prevent injury to the igniter from overheating. During the flow of alternating current in the igniter circuit, the ballast resistor 32 heats up slowly, and its resistance increases with temperature to gradually reduce the amount of current flowing through the igniter coil 6. This has the effect of providing initial relatively high heating of the igniter 6, with subsequent reduction in temperature of the igniter as the amount of current flow ing therethrough is reduced.

The improved apparatus provides an electrical interlock between the ignition circuit and the thermoelectric circuit whereby an alternating current is impressed upon the thermoelectric circuit whenever alternating current flows in the ignition circuit. In the embodiment illus trated in Figure 1, the electrical interlock is provided by the transformer 30 which has its primary winding 31 in the ignition circuit and its secondary winding in the thermoelectric circuit. The transformer 30 inductively connects or couples the thermoelectric circuit with the ignition circuit, so that whenever the ignition circuit is made, an alternating current having an amplitude greater than the difference between the steady running value and the drop-out value of the thermoelectric current is superimposed on the thermoelectric current flowing through the coil 23 and is compounded therewith. The current value is thereby caused to pass through and below the drop-out value of the current, and the electromagnet no longer has sufficient magnetic attraction for the armature 2G to hold the latter in the retracted position shown. As a result, the valve 17, if open, moves to closed position under the bias of the spring 19 to provide percent shut-off of the fuel.

In a thermoelectric circuit of the aforementioned character the normal current value may be approximately 400 milliamperes and the drop-out value may be milliamperes. If an alternating current having an amplitude of 300 milliamperes or more is impressed on the normal thermoelectric current, the compounded current will pass below the 115 milliampere drop-out value to actuate the valve 17.

To light the pilot burner 7 it is necessary to depress the reset button 25 and close the switch 42. As previously mentioned, the reset mechanism resets the armature 20 to the electromagnet and opens the valve 17 to permit fuel flow to the pilot burner 7, while at the same time preventing fuel flow to the main burner 8 by virtue of the flow interruption disk 46. Closure of the switch 42 causes alternating current flow through the transformer 39 to the igniter 6 via the ballast resistor 32 and the primary winding of the transformer 30. The igniter 6, therefore, heats up to provide ignition of the fuel issuing from the pilot burner. At the same time alternating current from the ignition circuit is impressed on the thermocouple circuit through the transformer 30, so that as the generator 9 heats up and generates a thermoelectric current, the compounded alternating and thermoelectric current has a value below the drop-out value. If the reset button 25 is released while the switch 42 is closed, the valve 17 closes the shut off all fuel flow. This is because the electromagnet cannot hold the armature in retracted position as long as alternating current is superimposed on the thermoelectric current by closure of the switch 42. It is therefore impossible for fuel to flow to the main burner 8 as long as the switch 42 is closed to provide 'energization of the igniter.

The improved apparatus provides an additional safety function in that if, during normal operation, the pilot burner 7 should go out, and the switch 42 immediately closed to energize the igniter 6 while the couple 9 is still hot and therefore generating thermoelectric current, the interlock providing superimposition of the alternatcurrent on the thermoelectric current on closure of seams said switch causes-the valve 17 to snap closed and prevent fuel flow to the main burner. If it were not for the aforementioned additional safety feature, injury to the operator could result if, while the couple 9 is hot and the switch 42 is closed, the thermostat 52 should call for heat and openthe valve 50, allowing raw gas to pour out of the main burner. lgnitionbf this gas could cause a flash-out at the furnace opening which flash-out could injure the operator. p

The proper procedure in setting the apparatus into operation is to openthe switch 42 and stop the flow of alternating current after the fuel at the pilot burner 7 has been ignited, and to thereafter release the reset button '25. This permits the eleetromagnet to be energized exclusively by thermoelectric current, and when so energized, it holds the valve 1 7 in open position. The valve is held open by the electromagne't until the current value in the coil 23 subsequently drops below the dropour value, whether said current drop be caused by pilot failure and resultant cooling of the generator, or by superimposition of alternating current on the thermoelectric current.

It is apparent that in the improved apparatus an electrical interlock is provided between the thermoelectric device 5 and the alternating current powered unit 6, whereby theth'ermoelectrie device is actuated whenever the alternating current device is energized. More specifically, the interlock closes the valve 5 and prevents all fuel flow to the main burner whenever the igniter 6 is energized. If the valve member 17 should be opened by the manual reset mechanism while the igniter is energized, fuel flow to the main burner is nevertheless prevented by the How interruption disk 46. Thus, whenever the igniter 76 is. energized it is impossible for raw gas to issue from the main burner and create a hazardous condition, only pilot gas flow being permitted at such times.

' While the drawings show the thermoelectric circuit induct'ively connected to the ignition circuit through a transformer, the superimposed alternating current need not necessarily be derived from the ignition circuit. It may be provided by a separate source, which may be connected directly or inductively to the thermoelectric circuit through a suitable electrical interlock which causes alternating current flow in the thermoelectric circuit whenever the ignition circuit is made.

. ,The' copending application of Russell B. Matthews, Serial No. 202,939, filed December 27, 1950, now Patent No. 2,649,767, illustrates one form of device for inductivelyrconnecting a thennoelectri'c circuit to a source of alternating current, and the invention contemplates the use of a device of this character suitably interlocked with an ignition circuit to cause alternating current flow in the thermoelectric circuit whenever the ignition circuit is energized. Obviously, the source of alternating current to which the last-mentioned device is connected may be the ignition circuit, or a separate source.

Figure 2 shows a modified form of the invention utilizing many of the same parts as the apparatus of Figure 1. The parts in Figure 2 indicated by primed numerals correspond to similar parts in Figure 1 indicated by the same numerals unpnmed. In Figure 2, a single transformer 34' having two secondary windings 33' and 29' is used in place of the transformer 34 and 30 of the form of the invention shown in Figure 1. On closure of the switch 42 the secondary winding 33 delivers alternating current to the igniter 6' via the ballast resistor 32 and conductors 37', 36', and 38, and the secondary winding 29' delivers alternating current to the coil 23' via the thermocouple 9' and conductors 27, 26' and 28. Except for the difference in the transformer arrangement, the apparatus of Figure 2 is identical to that of Figure 1. The operation of both of the illustrated forms of the invention is substantially the same.

While the illustrated embodiments of the invention utilize safety shut-off valves 5 and 5' which provide flow interruption and percent shut-off, the invention also has utility in systems utilizing safety shut-off valves without these features. In the latter case, the pilot burner fuel is taken from the supply pipe 14 upstream of the safety shutoff valve and may be controlled by a manually operable valve. The interlock affording positive closure of the main fuel line by the safety shut-off valve when the igniter is energized, is of particular utility in systems of this type.

The forms of the invention selected for illustration are for the purpose of disclosure only and are not intended to impose any limitations on the scope or use of the invention. Various changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated as may come within the scope of the claims.

What is claimed as the invention is:

1. In control apparatus for fluid fuel burning equipment, in combination, fuel burner and fuel supply means therefor, ignition means for said fuel burner including an electroresponsive igniter and an energizing circuit therefor, a flow control member associated with said fuel supply means and having fiow-permitting and flow-preventing positions, biasinig means for said flow control member urging the same toward. its flow-preventing position, said flowcontrol member being movable to its flow-permitting position against said bias, electric holding means operable when energized to retain said flow control member in its flow-permitting position when the latter is moved thereto against said bias, an energizing circuit for said holding means, flow-interruption means for cooperation with said fuel supply means to prevent fuel flow to said fuel burner during movement of said flow control memher .to its flow-permitting position, and interlock means comprising inductive means interconnecting said igniter and holding means circuits whereby on energizat-ion of said igniter an electrical potential is induced in said holding means circuit to render said holding moans inopcrative, whereby fuel flow to said fuel burner is rendered impossible whenever said igniter is energized.

2. In control apparatus for fluid fuel burning equipment, in combination, fuel burner and fuel supply means therefor, ignition means for said fuel burner including an electroresponsive igniter and an energizing circuit therefor, a flow control member associated with said fuel .member ur-ging the same toward its flow-preventing position, said flow control member being movable to its flowpermitting position against said bias, electric holding means operable when energized to retain said flow control member in its flow-permitting position when the latter is moved thereto against said bias, an energizing circuit for said holding means including a thermoelectric generator responsive to the heat of a flame, flow interruption means for cooperation with said fuel supply means to prevent fuel flow to said fuel burner during movement of said flow control member to its flow-permitting position, and means interlocking said igniter and holding means circuits whereby on energization of said igniter a current flow is induced in said holding means circuit, which induced current flow when combined with a current flow produced by heating of said thermoelectric generator renders said holding means inoperative whereby fuel fiow to said fuel burner is rendered impossible whenever said igniter is energized.

3. In control apparatus for fluid fuel burning equipment, in combination, fuel burner and fuel supply means therefor, ignition means for said fuel burner including an electroresponsive heating coil and an energizing cir cuit therefor including a source of alternating current, a flow control member associated with said fuel supply means having flow-permitting and flow-preventing positions, biasing means for said flow control member urging the same toward its flow-preventing position, said flow control member being movable to its flow-permitting position against said bias, electric holding means operable when enengized to retain said flow-control member in its flow-permitting position when the latter is moved thereto against said bias, an energizing circuit for said holding means including a thermoelectric generator responsive to the heat of a flame for producing a direct current in said holding means, flow interruption means for cooperation with said fuel supply means to prevent fuel flow to said fuel burner during movement of said flow control member to its flow-permitting position, and means interlocking said igniter and holding means circuits whereby an alternating current is superimposed on the direct current flowing in said holding means circuit to render said holding means inoperative and prevent fuel flow to said fuel burner whenever said igniter is energized by its energizing circuit.

4. In control apparatus for fluid fuel burning equipment, in combination, main and pilot burners and fuel supply means therefor, ignition means for said pilot burner including an electroresponsive heating coil and an energizing circuit therefor, a flow control member for said main and pilot burners associated with said fuel supply means and having flow-permitting and flow-preventing positions, biasing means for said flow control member unging the same toward its flow-preventing positioin, said flow control member being movable to its flow-permitting position against said bias, electric holding means operable when energized to retain said flow control member in its flow-permitting position when the latter is moved thereto against said bias, an energizing circuit for said holding means including a thermoelectric generator responsive to the heat of the pilot burner flame, flow-interruption means for cooperation with said fuel supply means to prevent fuel flow to said main burner during movement of said flow control member to its floW-permitting position, and means interlocking said igniter and holding means circuits to render said holding means inoperative whereby fuel flow to said main burner is rendered impossible whenever said igniter circuit is effective to energize said heating coil, irrespective of the condition of said pilot burner flame.

5. In control apparatus for fluid fuel burning equipment in combination, fuel burner and fuel supply means therefor, ignition means for said fuel burner including an electroresponsive igniter and energizing circuit therefor, a flow control member associated with said fuel supply means having first and second positions, biasing means for said flow control member urging the same toward its first position, said flow control member being movable to its second position against said bias, electromagnetic means operable when energized to retain said flow control member in its second position, and energizing circuit for said electromagnetic means, and interlock means comprising inductive means interconnecting said igniter and said electromagnetic means circuits whereby on energization of said igniter an electrical potential is induced in said electromagnetic means circuit to render said electromagnetic means inoperative, whereby fuel flow to said fuel burner is rendered impossible whenever said igniter is energized.

6. In control apparatus for fluid fuel burning equipment, in combination, main and pilot burner means and fuel supply means therefor, ignition means for said burner means including an electrorepsonsive heating coil and an energizing circuit therefor, a flow control member for said burner means associated'with said fuel supply means and having flow permitting and flow preventing positions, biasing means for said flow control member urging the same towards its flow preventing position, said flow control member being movable to its flow permitting position against said bias, electromagnetic means operable when energized to retain said flow control memher in its flow permitting position when the latter is moved thereto against said bias, an energizing circuit for said electromagnetic means including a thermoelectric generator responsive to the heat of the pilot burner flame, and means interlocking said igniter and electromagnetic means circuit to render said electromagnetic means inoperative whereby fuel flow to said main burner is rendered impossible whenever said igniter circuit is elfective to energize said heating coil irrespective of the condition of said pilot burner flame.

7. Control apparatus for fluid fuel burning equipment comprising in combination, first and second burners, electroresponsive ignition means for said second burner having an energizing circuit therefor, flow control means for said first and second burners biased toward a first and having a second position, electric holding means operable to retain said flow control means in second position when moved thereto, a low power energizing circuit for said holding means responsive to the heat of said second burner flame, flow-interruption means associated with said flow control means to prevent fuel flow to said first burner during movement of said flow control means to second position, and means interlocking said ignition means and holding means circuits to render said holding means inoperative whenever said ignition circuit is energized irrespective of the condition of said second burner flame.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,470 Betz Mar. 18, 1952 2,266,185 Fillo Dec. 16, 1941 2,269,157 Levine Jan. 6, 1942 2,290,048 Hildebrecht July 14, 1942 2,446,718 Ray Aug. 10, 1948 2,486,306 Main Oct. 25, 1949 2,505,730 Betz Apr. 25, 1950 2,607,406 Caparone Aug. 19, 1952 2,614,622 Eskin Oct. 21, 1952 2,679,560 Kunzler et al. May 25, 1954 2,680,478 Schultz et al June 8, 1954 2,720,614 Cairns Oct. 11, 1955 

